Blast and dust control plug



March 24, 1953 A. 1.. MADILL BLAST AND DUST CONTROL PLUG Filed May 11 1946 INVENI'OR 144/250 100/: M40114 ATTORNEYS Patented Mar. 24, 1953 BLAST AND DUST CONTROL PLUG Alfred Louis Madill, Vancouver, British Columbia, Canada Application May 11, 1946, Serial No. 669,118

8 Claims. (Cl. 102-30) This invention relates to a plug for controlling the blast and dust during and after blasting operations.

This plugis for use in blasting operations in which at least one hole is drilled in the rock, a charge of dynamite and a firing cap are placed in the hole, and after a fuse is led out of said hole, it is plugged and the shot is fired either electrically or by igniting the fuse.

The objects of this invention are to provide a blast plug which may be quickly and easily inserted in the hole, which jams more solidly in position the greater the force of the explosion, which includes means for accommodating and protecting the fuse, which has a relatively large surface contacting the sides of the hole, and which includes means for discharging a dustlaying material into the atmosphere during the blasting operation.

With these and other objects in view, the present invention consists essentially of a blast plug comprising a substantially conical wedge, a tubular wedge tapered in the opposite direction to the conical wedge and adapted to fit around the latter, and means for permitting the tubular wedge to expand when the conical wedge is driven into it, as more fully described in the following specification and illustrated by way of example in the accompanying drawings, in which Figure l is an elevation of one form of plug,

Figure 2 is an elevation, partly in section, of the plug turned at approximately right angles to the position of Figure 1,

Figure 3 is an end elevation of the plug,

Figure 4 is an elevation of the opposite end thereof, and

Figure 5 is an elevation, partly in section, similar to Figure 1 of an alternative form of plug.

Referring more particularly to Figures 1 to 4 of the drawings, H] is a substantially conical wedge formed of a relatively soft material and i l is a tubular wedge tapered in the opposite direction to the conical wedge adapted. to fit around the latter. The tubular wedge is preferably formed of a relatively soft material and/or is split longitudinally, as at i2, so that it will expand when the conical wedge is driven into it. The wedge it] is preferably enclosed within a conical casing is and a passage I5 is located therebetween, said passage being formed by a longitudinal groove in the side of the wedge. The casing may be formed with a tapered shoulder H5 at its small end.

The conical wedge 18 is preferably hollow and has a tapered plug ll formed of relatively soft material removably mounted in its large end, said plug being shaped to accommodate the groove of the casing which forms the passage I5.

This wedge is filled with a dust-laying material, such as, for example, lime powder.

The relatively soft material for these various elements may be any desired material, but it must be compressible and it is preferably fibrous, such as a soft cardboard.

After the charge and the firing cap have been:

placed in the hole and the fuse is led out of the hole, the fuse is threaded through the pas-- sage i5 where it is protected by the casing 4. The conical casing and wedge III are placed in the hole and then the tubular wedge is inserted in said hole and around the small end of the' casing or the shoulder It. A few sharp taps and the plug is locked in place. When the charge is fired, the force of the explosion drives the conical wedge and its casing into the tubular wedge causing the latter to expand so that the greater the force of the explosion the tighter the plug is jammed in the hole. The fact that the outer wedge is tubular ensures a large surface bearing against the wall of the hole, thus providing a powerful grip. The shoulder I 8 reinforces the.

the small end of the conical wedge into the at-' mosphere. The powder mingles with the dust caused by the blast and settles with it, and it absorbs moisture from the air, thus keeping the dust settled. This is a highly desirable feature since the dust is a great problem in mining and around other blasting operations. Furthermore, as the plug moves in the conical wedge, it presses the part thereof forming the passage I5 outwardly to close off the latter. Thus the plug completely closes the outer end of the wedge to keep the flame and force of the explosion in the hole.

In Figure 5, the conical wedge l8 fits directly into the tubular wedge Ii while the casing l4 and the passage l5 are omitted. In place of the plug H, a relatively large plug 26 fits into and extends outwardly from the large end of the conical wedge. This plug is provided with a central tube 2| extending therethrough and project- 3 ing into the inner wedge. This tube forms a passage for the fuse. A conical tube 22 formed of fibrous material fits inside the wedge l8 and the plug 26 rests on it and has an extension 23 fitting into it.

The plug 29 is filled with a dust-laying material and the force of the explosion shatters the plug and forces the material out around the plug where it mixes with the dust in the atmosphere. The explosion also drives the plug forwardly against the fibrous tube 22 causing the latter to buckle and fill the interior of the wedge IE3. This presses the walls of the wedge outwardly and it prevents dust and flame from passing through the wedge and out into the atmosphere.

What I claim as my invention is:

1. A blast plug comprisinga conical wedge formed of relatively soft material, said wedge being adapted to be fitted into a hole, a groove formed in the side of the wedge for the accommodation of a fuse, and a plug movably fitting in the large end of the wedge, said plug being driven into the wedge by the force of an explosion in the hole to press the part of the wedge forming the groove outwardly completely to close the outer end of the wedge.

2. A blast plug comprising a conical wedge formed of relatively soft material, said wedge being adapted to be fitted into a hole with its larger end closing the latter, and a tubular wedge tapered internally in the opposite direction to fit around the conical wedge and formed of relatively soft material, said tubular wedge being the same diameter as the larger end or the cone wedge and being split longitudinally for permitting the expansion thereof when the conical wedge is driven into it under force of an explosion in the hole, the material of the wedges permitting them to expand and become deformed completely to block the hole, and said tubular wedge providing a large unbroken surface from one side of the split to the other for gripping the whole wall.

3. A blast plug comprising a hollow conical wedge, formed of relatively soft material to be fitted into a hole with its larger end closing the latter, a plug movably fitting in the large end of the wedge, said plug being formed of relatively soft material, and a tubular wedge tapered internally in the opposite direction to fit around the conical wedge, said tubular wedge being the same diameter as the larger end of the cone wedge and being split longitudinally for permitting the expansion thereof when the plug is driven into the conical wedge under force or" an explosion in the hole, and said plug being driven throu h the conical wedge to expand the latter further to expand the tubular wedge.

4. A blast plug comprising a conical casing, a hollow substantially conical wedge fitted in the casing, said wedge being filled with a dust-laying material, a passage formed between the wedge and casing, a tubular Wedge tapered in the opposite direction to fit around the casing, means for permitting the tubular wedge to expand when the conical wedge is driven into it, said casing, conical wedge and tubular wedge being formed of relatively soft material, and a tapered plug removably mounted in the large end of the conical wedge.

.5. A blast plug comprising a conical wedge formed of relatively soft material to be fitted into a hole, a tubular wedge tapered in the opposite direction to fit around the conical wedge and fit in the same hole, a groove formed in the side of the conical wedge for the accommodation of a fuse, and a plug movably fitting in the large end of the conical wedge, said plug being driven into the wedge by the force of an explosion in the hole to press the part of the wedge forming the groove outwardly completely to close the outer end of the wedge.

6. A blast plug comprising a hollow substantially conical wedge, a dust-laying material in the hollow wedge, a groove formed in the side of the wedge for the accommodation of a fuse, a tubular wedge tapered in the opposite direction to fit around the conical wedge, said tubular wedge being split longitudinally to permit it to expand when the conical wedge is driven into it, said conical and tubular wedges being formed of relatively soft material, and a tapered plug removably mounted in the large end of the conical wedge.

'7. A blast plug as claimed in claim 2 including a hollow plug removably fitting in the larger end of the conical wedge, said plug being formed of relatively soft material, a central tube extending through theplug and projecting into the conical wedge, and a dust-laying material in the plug.

8. A blast plug as claimed in claim 2 including a plug removably fitting in the larger end of the conical wedge, a conical tube formed of fibrous material fitting inside the conical wedge, said plug resting on the end of the fibrous tube, and a central tube extending through the plug and projecting into the conical wedge.

ALFRED LOUIS MADILL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 971,264 Goodrow Sept. 27, 1910 2,115,388 'Heitzman Apr. 26, 1938 2,170,929 Madill Aug. 29, 1939 2,257,063 Mossman Sept. 23, 1941 2,388,232 Tappan Oct. 30, 1945 FOREIGN PATENTS Number Country Date 23,498 Great Britain of 1899. 

